There are many different types of combination thermostat tip switches known in the prior art. One such type is the one disclosed in U.S. Pat. No. 3,201,548 which is assigned to the same assignee as the present invention. Generally, this type of thermostat tip switch assembly includes a pair of contact leaves mounted on a stack assembly and a thermostatic bimetal leaf mounted on the stack which was adapted to move a pair of contacts on the leaves out of engagement with one another. A position sensitive pendulum is mounted on one of the contact leaves and acts to operate the same two contacts. The problem with this type of combination thermostat-tip switch is that the contacts occasionally weld together which renders the pendulum ineffective to disengage the contacts regardless of the position of the switch.
By increasing the number of contact interfaces through which electrical current must travel, the likelihood that the tip switch portion of a combination thermostat tip-switch will fail to perform its intended function is decreased because the probability of all the contact interfaces welding at the same time is decreased. Thus, the combination thermostat tip switch shown in U.S. Pat. No. 3,964,004 is increased in reliability insofar as the tip switch is concerned.
However, while the combination thermostat tip switch disclosed in U.S. Pat. No. 3,964,004 provides a greater degree of safety over prior art designs, it does so with a substantial increase in cost and size. Thus, it would be desirable to provide the same degree of safety in a combination thermostat tip switch as the device disclosed in U.S. Pat. No. 3,964,004 but reduced in cost and size.